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Article #283Re: Best way to power array of LEDs?
From: John Woodgate
Date: Fri, 04 Oct 2002 12:59
Date: Fri, 04 Oct 2002 12:59
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2485 bytes
I read in sci.electronics.design that Uwe Zimmermann <uwezi@kth.se> wrote (in <3D9D5939.CD795C11@kth.se>) about 'Best way to power array of LEDs?', on Fri, 4 Oct 2002: >You then connect the drain of the transistor to the positive supply and >the gate/source to the anode of the first LED in each chain. The cathode >of the last LED is connected to the negative supply. This is an *extremely* unreliable circuit, because it has no protection against the large transients, of both polarities, that occur on vehicle electrical supplies. Don't bother with adding transistors just to get rid of a few resistors (or maybe add a few more, and MOVs and capacitors and fuses ...). KISS! -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Interested in professional sound reinforcement and distribution? Then go to http://www.isce.org.uk PLEASE do NOT copy news posts to me by E-MAIL!
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X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 112d1e,4ef4c9d4aea85e1f X-Google-Attributes: gid112d1e,public X-Google-Thread: 10d137,4ef4c9d4aea85e1f X-Google-Attributes: gid10d137,public X-Google-Thread: 1118be,4ef4c9d4aea85e1f X-Google-Attributes: gid1118be,public X-Google-Thread: 1131b0,4ef4c9d4aea85e1f X-Google-Attributes: gid1131b0,public X-Google-Thread: 103407,4ef4c9d4aea85e1f X-Google-Attributes: gid103407,public X-Google-ArrivalTime: 2002-10-04 07:08:42 PST Path: arc1-ca.pugleaf.net!archiver1.google.com!news1.google.com!newsfeed.stanford.edu!news-spur1.maxwell.syr.edu!news.maxwell.syr.edu!newsfeed.icl.net!newsfeed.fjserv.net!kibo.news.demon.net!news.demon.co.uk!demon!jmwa.demon.co.uk!jmw From: John Woodgate <jmw@jmwa.demon.contraspam.yuk> Newsgroups: sci.electronics.components,sci.electronics.design,alt.engineering.electrical,aus.electronics,sci.electronics.repair Subject: Re: Best way to power array of LEDs? Date: Fri, 4 Oct 2002 13:59:59 +0100 Organization: JMWA Electronics Consultancy Lines: 18 Message-ID: <B7hloTAPDZn9EwGz@jmwa.demon.co.uk> References: <0001HW.B9C26E7400A7161B165FEAC0@news.covad.net> <3D9D32DE.93168158@autometer.de> <3D9D5939.CD795C11@kth.se> Reply-To: John Woodgate <jmw@jmwa.demon.co.uk> NNTP-Posting-Host: jmwa.demon.co.uk Mime-Version: 1.0 X-Trace: news.demon.co.uk 1033740522 29367 158.152.135.100 (4 Oct 2002 14:08:42 GMT) X-Complaints-To: abuse@demon.net NNTP-Posting-Date: Fri, 4 Oct 2002 14:08:42 +0000 (UTC) X-Newsreader: Turnpike (32) Version 4.01 <5Z8C9wtxbnpWyFnyfFzqmVF739>